Off Road Go Kart Page
Off Road Go Kart Page
This page is dedicated to some of the small projects that I've done on a Yerf
Dog 3203 off road go kart. One of the first
things that become obvious on this go kart was that it was seriously gutless!
Even though it had a 6.5HP Tecumseh engine, the first time I took it out I was
wondering where the other 6 horse were hiding! It wasn't quite that bad,
but it was a big disappointment in terms of power and performance. Even
the gentlest hills or inclines tended to bog the engine and nearly stall it.
Since I've tinkered on engines most my life, I decided to try and do something
about the lack of power. After a bit of tinkering on the Tecumseh 6.5HP
engine and some adjustments to the Comet torque converter, the kart was much
more fun to drive. It was finally able to climb some hills and it scooted
around pretty well. I won't go into all the details of modifications to the Tecumseh 6.5HP engine since the kart no longer has this engine. Just briefly... before selling the Tecumseh engine, I advanced the ignition timing around 7 degrees with an offset flywheel key. This made a nice increase in power/torque. I also re-jetted carb for our higher elevation and this made the engine run stronger. Modified the carb so that it would open full throttle (instead of around 75% like it came from the factory). Ported the intake manifold to remove some terrible casting flaws (and machining flaws from the factory). Removed the governor to allow engine to rev up higher - but this didn't really seem to make that much difference on our kart because the torque converter was shifting up too soon and not allowing the engine to get into higher RPM's anyway. By the time I sold the original Tecumseh engine, it did run strong. It definitely ran much stronger than as it came on the kart originally! Even so, I decided to sell it because I wanted a better quality engine that had more potential. You can read more about my choice by clicking on the link down below regarding "ENGINE SWAP".
This is a "family kart", so I do not have any radical plans for it. If I were single, I'd probably be shooting for a kart that could pull wheelies and roast the tires on pavement... probably something with a motorcycle engine. But, since this is a family kart (and since I'm not as crazy as I used to be), I am being much more conservative on what I will do to this kart. I take it out with my 3 older children (they are still quite young) strapped in a kid's booster car seat next to me. They are securely strapped in with the kart's 3 point seat belt and they wear their helmet. They enjoy tearing up a vacant field with the "old man". The youngest to ride along so far is 2 years old.
Besides being gutless from the factory, another weak point on the Yerf Dog 3203 is the stock "pogo stick" shocks. They are not hydraulic dampened, so they tend to bounce a lot. I picked up a set of 4 Azusa shocks (1700-136) for the kart. Click here to see a picture of this shock. You can't tell from the B&W picture, but the springs are red so they go well with the red 3203 color. They made a huge difference in the way the kart handles the bumps. Much better than stock! The Azusa shocks have progressive dampening and adjustable spring preload. Because the bolt holes on the 1700-136 Shock ends were bigger, I bought some bigger bolts and nuts and then drilled out the shock mounts on the kart to match. Easy to do, and definitely worth the effort and expense to upgrade to some real hydraulic shocks! Since buying my Azusa shocks, I ran across a full set of 4 bolt on hydraulic shocks for less money.
CLICK BELOW TO SEE SOME OF THE MODIFICATIONS I'VE DONE TO THE YERF DOG 3203:
ROBIN EX21 ENGINE SWAP (added
09-10-03) HIGH FLOW AIR
FILTER SYSTEM (added 09-13-03)
OTHER MISC. ACCESSORIES INSTALLED ON YERF DOG 3203
(added 09-20-03)
RECALIBRATED TORQUE CONVERTER & CHANGED DRIVE SPROCKET (added 10-21-03)
MORE POWER!... THE ULTIMATE SOURCE OF POWER